When you design a Web page using frames, you expect visitors to start at the address of the frameset holder, for example, default.htm. However, people who are linking from a search engine may end up bypassing the frameset. The link points directly to a page that was never meant to stand alone. You can gently nudge visitors to the “front door” by using a little JavaScript at the very start of each page that sits inside the frameset. In this example, left.htm, the script checks to see if the current page is the top of the frameset. If it is, the script redirects the browser to the container page, default.htm.
Left page
Click here
Don’t put the script in your frameset page or you’ll create an endless loop in which the only way out is to close the browser.